The iPhone 15 Pro and iPhone 15 Pro Max supported Thunderbolt 3 thanks to the A17 Pro USB controller, but the feature never made it
A string of rumors before the iPhone 15 Pro and iPhone 15 Pro Max announcement stated that both models would feature a USB-C port that supports Thunderbolt 3 ports. Unfortunately, Apple has limited the bandwidth to 10Gbps, whereas Thunderbolt 3 has a throughput of 40Gbps. However, one tipster states that the A17 Pro powering both devices has the same USB 3 controller as the M1, meaning it should have supported Thunderbolt 3, but it appears that the feature might have been removed for various reasons.Thunderbolt 3 support would likely have added to the total cost, so the A17 Pro is limited to the USB 3.2 Gen 2 standard
Instead of the older USB controller present on chipsets like the A12X, A12Z, or even the A16 Bionic, ShrimpApplePro states that the A17 Pro features the same crucial hardware as the M1 that allows Thunderbolt 3 connectivity right out of the box, but for various reasons, the feature did not make it to the iPhone 15 Pro or iPhone 15 Pro Max.
